title: Ecotoxicological assessment of acid mine drainage: electrophysiological changes in earthworm (Aporrectodea caliginosa) and aquatic oligochaete (Lumbriculus variegatus).
abstract: Ecological health of 15 sites in two mining areas on the West Coast of the South Island, New Zealand, was assessed using a non-invasive electrophysiological technique. The conduction velocity (CV) changes in the medial giant fibres (MGF) of the terrestrial earthworm Aporrectodea caliginosa were measured on days 0, 1, 2, 4, 7, 14, and 21 following exposure to soil and/or sediment from six acid mine drainage (AMD) sites, and aquatic oligochaete Lumbriculus variegatus at 0, 3, 6, and 24 h following exposure to water from 14 AMD sites. The colour of the soil/sediments varied from red-brown to black with pH ranging from 4.46 to 7.37. The colour of AMD water samples varied from clear, black, brown to orange, and the pH ranged from 2.99 to 7.66. The CV decreased progressively in A. caliginosa exposed to most soil and sediment samples from the AMD sites (compared with controls exposed to soil from an organic farm) and this was most evident in measurements taken at 7 days. Based on the CV measurements taken on day 7, sites 3 > 2 > 1 were significantly (P < 0.05) the most toxic to earthworms. The CV of L. variegatus exposed to AMD water sampled from many sites also decreased progressively and this was significantly lower than the controls in the measurements taken at 24 h from sites 3 > 9 > 7 > 11. It is proposed that MGF CV in A. caliginosa and L. variegatus worms can be used as a non-invasive, sensitive, biomarker to monitor the toxicity of AMD sites.
authors.affiliation: Faculty of Agriculture and Life Sciences, Lincoln University, PO Box 84, Lincoln 7647, New Zealand. Ravi.Gooneratne@lincoln.ac.nz
authors.forename: Ravi
authors.initials: R
authors.lastname: Gooneratne
authors.forename: Andreas
authors.initials: A
authors.lastname: Buser
authors.forename: Phil
authors.initials: P
authors.lastname: Lindsay
authors.forename: Martin
authors.initials: M
authors.lastname: Wellby
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects; D054750:Ecotoxicology; D055724:Electrophysiological Phenomena; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D008906:Mining; D009520:New Zealand; D009835:Oligochaeta / Q000187:drug effects* / Q000502:physiology; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical